Merotricarbocyanine dye and photographic emulsion



the non-metallic atoms necessary to complete' a continuation-in-part of my copending appli-V erocyclic nucleus.

Patented Jan. 9, 1940l UNITED STATES PATENT OFFICE MEROTRICARBOCYANINE DYE AND j i PHOTOGRAPHIC EMULSION Leslie G. s. Brooker, Rochester, N. Y., assinor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application April 26, 1937, Serial No. 138,953

complete a six-membered heterocyclic nucleus, such as one of the pyridine series or one of the quinoline series, for examplev -methylquinoline or 5,6-benzoquinoline. Z can represent the nonmetallic atoms necessary to `complete a ve- 5 membered heterocyclic nucleus, particularly a K live-membered heterocyclic nucleus containing a nuclear nitrogen and nuclear sulfur atomas in the case of a rhodanine nucleus, for example. Z can represent the non-metallic atoms necessary to complete an oxazoledione nucleus, for example a 3-'allryl2thio2,4-oxazoledioneA nucleus or a l-alkyl yoxindole nucleus, such as l-ethyl'- oxindole or l-ethyl-Z-thio-oxindole orl like fivemembered 'or six-membered heterocyclic nu- 15 clei.

My new dyes can be prepared by reacting a cyclammonium quaternary salt containing an acylanilino-A,1135hexatrienyl,group in the alpha or gamma position, i. e. one of the so-called re' 20 active positions, with a heterocyclic compound containing a nuclear reactive methylene group adjacent to a nuclear carbonyl group, such as a nuclear oxocarbonyl (commonly called merely carbonyl) or a nuclear thiocarbonyl group. The lreactions are advantageously carried out in the presence of a diluent which allows of a homogeneous reaction mixture and from which the dye will separate at least upon chilling. Lower aliphatic alcohols, i. e. alcohols of one to four carbon atoms, are suitable. The reactions are further advantageously carried out in the presence of a basic condensing agent. 'I'he quantity of condensing agent is advantageously suiiicient to bind the elements of acid eliminated fromthe reacting molecules. Sodium hydroxide, sodium ethylate or potassium acetate can be employed for example. However, the condensing agent is advantageously a strong organic base, i. e. one having a dissociation constant substantially greater than that of pyridine. Trialkylamines, such as triethylamine or triethanolamine, dibutylamine, N-methylpiperidine, piperidine and'v diethylamine are suitable, for example. Heat accelerates the formation of my new dyes.

My new dyes can also be prepared by reacting an acylated condensation product of a heterocyclic compound containing a reactive nuclear methylene group adjacent to a nuclear carbonyl group with a glutaconic aldehyde dianilide salt 50 with a 'cyclammonium quaternary salt having a reactivealkyl group in the alpha or gamma position. `The diluents and condensing agents mentioned above are advantageously employed. as above. This second stated method is advan- /f 9 Claims.

This invention relates to merotricarbocyanine dyes and photographic emulsions containing the same.

The application is a continuation-impart of my copending application Serial No. 752,036, led November 8, 1934, (United States Patent No. 2,078,233, dated April 27, 19M) which is in turn cation Serial No. 739,502, led August 11, 1934.

An object ofy my invention is to provide new dyes which can be called merotricarbocyanine dyes. A further object is to provide a process for the preparation of such dyes. A still further object is to provide photographic emulsions containing such dyes. A still further object is to provide photographic emulsions sensitized for the far-red and infra-red region of the spectrum. Other more specic objects will be apparent hereinafter from the speciiication and claims.

My new dyes can be represented by the following general formulas:

and

wherein A represents a divalent atom of the oxygen group, such as oxygen or sulfur, for vex,- ample, D represents a vinylene or phenylene group, R represents an alkyl group, Y represents a heterocyclicv nucleus and Z represents theas non-metallic atoms necessary to complete a het- More specically, in the above formulas, R' can represent an alkyl group, such as methyl, ethyl, n-butyl, isoamyl or allyl for example, Y can represent the non-metallic atoms necessaryv to complete a five-membered heterocyclic nucleus, such as one of the thiazole series, for example 4-methylthiazole, 4-phenylthiazo1e, 4,5-diphenylthiazole, benzothiazole, 5-chlorobenzothiazo1e or. naphthothiazoles, or one of the oxazole series, for example -4-methyloxazole, 4-phenyloxazole, benzoxazole, ornaphthoxazoles, orv one of the selenazole series, for example 4-methylselenazole, 4-phe'ny1selenazole or benz'oselenazole, or one of the indolenine series, for example 3,3- dialkylindoline, or a thiazoline nucleus, orl a selenazoline nucleus for example. Y can also represent the non-metallic atoms necessary to tageously employed in preparing certain of my new dyes, for example those containing a quinoline nucleus linked through its '4-position or those dyes containing a 4-methylthiazole or 4- phenylthiazole nucleus or a benzoselenazole nucleus. I

While the process of preparing my new dyes is subject to Variation, particularly with respect to the natures and proportions of the reactants, the nature and proportion of the condensing agent, the nature and quantity of the diluent, the temperature, the time of reaction and the method of isolation and purication of the dyes, the following examples will serve to teach those skilled in the art the manner of obtaining my new dyes.

azyldene) herradzenylidene l -rhodan'ne 1.25 g. (1 mol.) of 1-(G-acetanilido-AlN5-hexatrienyi) -benzothiazole ethicdide and 0.75 g. of 3- ethyl-2-thio-2,4oxazoledione. were refluxed in about 10 cc. of. absolute ethyl alcohol containing 0.2 g. (1 mol.) of piperidine for about 10 minutes. The dye separated from the chilled reaction mixture. It was washed well with methyl alcohol. It was recrystallized first from methyl alcohol and then from ethyl alcohol and obtained as minute green crystals having a silvery reflex and melting at 214 to 216 C. with decomposition. Its ethyl alcoholic solution was blue.

EXAMPLE 3.-3-eth3/Z-5- (3-ethyl-4-phenyZ-2(3) thazylidene)hea;adienylidenel rhodanz'ne EXAMPLE 4.-,-3-ethyz-5-uz-ethyz-1(2) #benzosezenazylidene) hezadz'enylidene] -rhodam'ne i S c EXAMPLE 5.-,-3-et'hyl- 5- i (1 -ethyl-I (4) -quinolylz'- dene) hemadienylicienel -rhodamne N-CaBi 0.9 g. (1 mol.) of 5-(B-acetanilido-A-'l-pentadienylidgn) -3-ethylrhodanine and 1.5 g. (2 mol.) ofllpidine ethiodide were refluxed in about 20 cc. of absolute ethyl alcohol containing 1.0 g. (1 mol.+300% excess) of triethylamine for about 15 minutes. The dye separated from the chilled reaction mixture. It was ltered and washed well with methyl alcohol. It was twice recrystallized from a mixture of methyl alcohol and pyridine and obtainedas green crystals, melting at 198 to 200 C. with decomposition. Its methyl alcohol-pyridine solution was blue.

Instead of S-ethylrhodanine, unsubstituted rhodanine, S-phenylrhodanine, S-carbethoxymethylrhodanine, 3- (p-aminophenyD -rhodanine, l-ethyl-oxindole, 1.-ethyl2 -thio-oxindole, 3-alkyl- 2-thio-2,4oxaz0ledione or like five-membered or six-membered heterocyclic compounds can be employed, e. g. thiobarbituric acid.

In the above last three examples, the excess of basic condensing agent is advantageous, giving rise to a higher yield ofthe dye. Likewise the excess of cyclammonium quaternary salt is advantageous in order to secure better yields. The cyclammonium Quaternary salt is advantageously an alkiodide though other Quaternary salts can bey employed, e. g. alkylsulfatesor p-toluenesulfonates.

The cyclammonium quaternary salts containving a 6-acylanilido-Al-hexatrienyl group in a reactive position can-be prepared from cyclammonium quaternary salts containing a reactive alkyl group in a reactive position and a glutaconlc aldehyde dianilide salt by heating the materials together in an organic acid anhydride, advantageously acetic anhyride. The following procedure is illustrative:

5.8 g. (l mol.) of l-methylbenzoxazole ethiodide or 6.1 g. (1 mol.) of l-methylbenzothiazole ethic'- dide and 5.5 g. (1 mol.) of glutaconic aldehyde dianilide hydrochloride were heated in about 25 cc. of acetic anhydride for from 5 to 10 minutes. The reaction mixture was chilled and the hexatrienyl compound precipitated by adding diethyl ether. The precipitated product was stirred with acetone, ltered and nally washed with acetone.

Cyclammonium alkyl halides, particularly alkiodides, are advantageously employed though other quaternary salts can be employed, forexample the alkyl sulfates or toluenesulfonates.

The acylanilido-A214-pentadienylidene compounds can be prepared by reacting a glutaconic aldehyde dianilide salt with a compound con' taining a nuclear reactive methylene group adjacent to a nuclear carbonyl or thiocarbonyl group by heating the materials in the presence of a basic condensing agent advantageously employing a diluent, such as a lower aliphatic alcohol. 'I'he condensation product so` obtained is then acylated. The following procedure is illustrative:

6 .4 g. (1 mol.) of S-ethylrhodanine, 11.2 g. (1 mol.) of chloride, 50 cc. of absolute ethyl alcohol and 4 g. (l-mol.) of triethylamine were reuxed for from 3 to 5 minutes. 'Ihe reaction product separated from the chilled reaction mixture. It was iltered` 01T and dried. The dried reaction product was placed in cc. of acetic anhydride and the mixture heated to boiling and then quickly chilled. The acylated compound separated. It was i'lltered off and dried. Strong organic bases, particularlyV triethylamine are advantageously employed in preparing these intermediates.

My new dyes, particularlythose containing a rhodanine nucleus, sensitize photographic emulsions for the far-red and infra-red regions of the spectrum in a novel and useful manner. My invention is particularly directed to the customarily employed silver halide emulsions, especially the silver chloride and bromide emulsions, which can contain other salts which may be light-sensitive. My invention is further particularly directed to the customarily `employed gelatin emulsions. However, the gelatin can be replaced with any other carrier which has substantially no deleterious effecten the light-sensitive materials, e. g. a cellulose derivative or a resin.

yIn the preparation of photographic emulsions sensitized with my new dyes, itis only necessary to thoroughly disperse a small amount of the dyes in an ordinary photographic emulsion. The suitable and most economical concentration for any given emulson will be apparent to those skilled in the art, upon making the ordinary tests and observations customarily used in the art of emulsion making. To prepare a gelatinosilver-halide emulsion the following procedure is satisfactory: A quantity of the dye is dissolved in a suitable solvent, for example methyl alcohol, ethyl alcohol or pyridine, and a volume of this solution (which may be diluted with water) containing from 1/5 to 5 mg. of dye is slowly added glutaconic aldehyde dianilide hydro-y to about 1000 cc. of an ordinary fiowable gelatinosilver-halide emulsion, withstirring. The dye is thoroughly incorporated. lWith the more powerful of my new sensitizing dyes 1 mg. of dye per 1000 cc. of emulsion will suiice to produce maximum sensitizing effects with the ordinary gelatino-silver-halide emulsions. i'

'Ihe above statements are only illustrative and are not to be understood as limiting my invention in any sense, as it will be apparent that the'se dyes can b e incorporated by other methods in many of the photographic emulsions customarily employed in the art, such, for instance, as by bathing a plate or nlm, upon which an emulsion has been coated, in a solution of the dye in an appropriate solvent, although such a method is ordinarily not to be preferred. The claims are intended to cover anyA combination of these new dyes with a photographic emulsion, whereby the dye exerts a 'sensitizing effect upon the emulsion as well as a photographic element comprising a support, ordinarily transparent, upon which the light-sensitive emulsion is coated or spread and permitted to set or dry.

The accompanying drawing `is by way of illustration. Each figure is a diagrammatic reproduction of a spectrogram showing the sensitivity of an ordinary gelatino-silver-bromide emulsion containing one of my new dyes. In Fig. 1, the curve represents the sensitivity of an ordinary gelatino-silver-bromide emulsion containing 3- ethyl -5- (2-ethyl-1 (2) -benzothiazylidene) hexadienylidenel2-thio2,4oxazoledione. In Fig. 2, the curve represents the sensitivity of an ordinary gelatino-silver-bromide emulsion containing 3- ethyl-5-[(3-ethyl-4-phenyl 2(3) thiazylidene) hexadienylidenel -rhodanine. In Fig. 3, the curve represents the sensitivity of an ordinary gelatinasilver-bromide emulsiony containing 3-ethyl-5- (2-ethyl-1(2) -benzoselenazylidene) hexadienylidenel -rhodanine.

Still further illustrations of my new emulsions sensitized for the infra-red could be given, but the foregoing will suice to teach those skilled in the art the principles of sensitizing photographic emulsions for the far-red and infra-red with my new dyes.

My new dyes can be employed in the construction of light lters.

My new dyes can probably exist in two forms, illustrated as follows:

What I claim as my invention and desire to be secured by Letters Patent of the United States is:

1'. A photographic silver halide emulsion containing a'sensitizing merotricarbocyanine dye.

2. A photographic gelatino-silver-halide emulsion containing a sensitizing merotricarbocyanine dye.

3. A photographic gelatino-silver-halide emulsion sensitized with a 3a1kyl5-[(2alkyl1(2) benzotliiazylidene) hexadienylidene] -rhodaiiina 4. A photographic gelatino-silver-halide emulsion sensitized with 3ethyl5[(2-ethy1-1-(2)- benzothiazylidene) hexadienylidenel-rhodanine.

5. A photographic gelatino-silver-halide emulsion sensitized with a 3a1kyl-5-[(2alkyl1(2) benzoxazylidene) hexadienylidenel-rhodanine.

6. A photographic gelatino-silver-halide emulbenzothiazylidene) hexadienylidene]-2thio-2,4.

sion sensitized with 3ethy15[(2eihy11(2) benzoxazyiidene) hexadienylidenel-rhodanine.

7. A photographic gelatinosilver-halide emulsion sensitized with a 3-a1ky1-5-[(2 5 benzothiazylidene) hexadienyiidene]-2-thi02,4

oxazoledione.

8. A photographic geiatino-silver-halide emulcarbocyanine dye.

LESLIE G. S. BROOKER.. 

